l6& DR. KLEIN. 



than in others. The fibrils of the intracellular network are also 

 here directly connected with the intranuclear ones ; hence the 

 membrane of the nucleus appears dotted, owing to its being 

 interrupted by the passage of those fibrils. 



The layer of columnar epithelial cells hitherto described forms 

 one — now doubt the chief — part of the wall of a tube of the 

 epididymis, but there is another layer of small cells with nuclei, 

 generally shrunk and deeply stained in logwood specimens, inside 

 the membrane (Becker, Henle, Kolliker). This latter contains 

 a perceptible amount of unstriped muscle fibres (Henle, KoUiker) . 

 See fig. 9, Plate YII. 



The nuclei belonging to the columnar cells lie, as usual, in the 

 outer third of the cell-body ; in sections, however, hardened 

 simply in spirit, it appears as if the nuclei had a more 

 irregular position, appearing in some cells in the inner, in others 

 near the middle, and in still others in the outer part. Instead 

 of finding the nuclei all arranged in a definite zone — speaking of 

 the epithelium as a whole — we see that they appear distributed 

 almost over the whole thickness of it (see fig. 9, a), except a 

 small inner zone that remains free of them. This becomes 

 easily explained if we compare with it a section through epi- 

 didymis (of the same animal) in which before being placed in 

 spirit the lymphatics had been injected ; that is to say, the in- 

 tertubular spaces having been filled first, the organ was prevented 

 from shrinkmg. Inasectionof such an epididymiswefindthenuclei 

 approximately keeping within a definite zone of the epithelium. 



Out of several measurements of tubes of an epididymis hardened 

 simply in spirit I find : 



The thickness of epithelium 0'037 mm. 



The thickness of membrane (incl. muscle-fibres) . 0'0055 mm. 



For those of the epididymis of the other side, having been 

 first injected and then hardened in spirit, I find : 



The thickness of epithelium , . . 0'026 mm. 



The thickness of membrane (iucl. muscle-fibres) . O'OOS mm. 



That is to say, the thickness of the epithelium of the former 

 relates to that of the latter as 3 to 2. The epithelial cells in 

 the former case being more pushed together than in the latter 

 give the impression as if laminated, in the same manner as 

 mentioned by Arnold for the epithelium of the papillae of tongue 

 of frog, referred to on a previous page. 



3. T/te Gland-cells in tke Submaxillary Gland, 

 {a) In the dog. — As is known from the investigations of 

 Heidenhaini the gland cells of the submaxillary gland of dog are 



' E. Heidenhain, ' Studicu des physiol. Institutes'zu Breslau/ 1868. 



